The new tanks are fitted with three-quarter
bridge scrapers for the activated sludge
process (ASP). A&J Fabtech also supplied
GRP launders, a drop box, weir plates, a
weir cleaning system, dipping scum box,
slip rings, loss of rotation sensors, torque
limiting sensors, and a scum concentration
collection system.
Refurbishing the existing tanks included
removal of their existing three-quarter
bridges and installation of new ones, while
the Mckinney baffles were upgraded from
5m to 8.2m diameter to provide enhanced
flow control in the effluent channel.
As with the new tanks, a weir
cleaning system, dipping scum box,
slip rings, loss of rotation sensors,
torque limiting sensors and scum
concentration collection
system have also been provided.
The increased treatment capacity,
especially in terms of secondary treatment
processes, has been instrumental in
reducing the ammonia levels in the final
effluent that is discharged to the River
Don. Under the European Freshwater Fish
Directive, the treatment works is required
to achieve a level of 3 mg/l or less of
ammonia in order to comply.
Since the refurbishment of Blackburn
Meadows, there have been regular
sightings of trout in the city centre reaches
of the River Don.
“It’s the first time such fish have been so far
upstream in over 100 years, and is one of
the key indicators of the project’s success”
says Shaun Brosnan. “There are plans
to reintroduce salmon too, something
that would have been completely
inconceivable just a few years ago.”
www.ajfabtech.com